Dental articulator



Feb. 8, 1938. H. BOATNER 2,107,283

' DENTAL ARTICULATOR l Y AOriginal Filed Oct, 28, 1935 2 Sheets-Sheet 1 Fig. 1

ATTORNEY.

Feb. 8, 1938. H. BoATNEF DENTAL ARTICULATOR original Filed ootj 28, 1935 2 Sheets-Sheet 2 DH-IEDRAL ANGLB 39 ZT/ INVENTOR.

ATTORNEY.

Patented Feb. 8, 1938 Y UNITED STATESv PATENT OFFICE Original application October 28, 1933, Serial No.

Divided and this application August 26, 1935, Serial No. 37,872

2 Claims.

The present invention relates to articulators, and to make more clear the construction and operation of the articulator, it is necessary to state some general principles about articulators 5 in general and the one forming the subject matter of the present application in particular.

Dental articulators are so formed that models of the human jaws can be supported and sets of artificial teeth articulated thereon, and movements of the articulator can be made in more or less imitation of the natural movements of the human jaws.

Dental articulators, as is well known to those skilled in the art of dentistry, can. be used in many other ways in the different branches of dentistry. Most of the articulators of the present time, outside of the plain line, are made adjustable and the patient is requested to make certain movements and the articulator is adjusted to these records for use in the construction of the sets of teeth.

An objection to this method is that the move ments cannot be made in different planes, since it is not known where these planes are located in the head. VAnother objection is that these movements are made, or are attempted to be made, with bases of the bite not being rigidly attached to the gums and the bases are liable to shift during movements, which could not be detected; the results are therefore uncertainand not definite.

A still further objection to the above method is that the planes of the bite plates would interfere with the freedom of the movements and we are liable to think we are getting the movements, when in reality we are only registering the planes of the bite plates.

Another objection is that since it is not known how to make the planes of the bite plates in a true horizontal plane, the planes of the bite plates being in contact and inclined to the horizontal plane, they would register differently during movements in various individuals as the inclinations varied to the horizontalplane.

Many other obstacles can occur in our attempts to obtain the movements of the jaws, and since we do not have a standard to go by to compare th-e results of dierent movements, all attempts are indefinite and not scientific. Therefore, in order to overcome the above mentioned difficulties, we standardize the movements by using hexagonal prisms terminated by three equally inclined planes as guides in the various movements of the articulator, which is of such a construction that it makes the artificial teeth move in the same planes or parallel planes as the guiding planes.

l As this method is a radical and entirely new departure from the conventional methods heretofore followed it will be necessary to very briefly explain the basic principles involved and why the terminated prisms are used.

In order that the. movements may be symmetrical and standardized, we chose the rhombic dodecahedron, a .natural solid found in nature, as the solid that has the dihedral angles and inclined planes that we desire to use as our guiding planes in our articulator. y

The dihedral angles oi the faces are all 120 degrees, and it has l2 faces, each of which isa rhombus. The plane angles of the faces are 109 degrees 28' and 70 degrees 32.

But in order to use this dodecahedron in our ,articulaton we must elongate the sides of it preserving the same angles and the plane inclina.- tions, but they side planes must be of such a length that we can attach the form to the plates of our articulator and observe the movements.

Our dodecahedron will then become a hexagonal prism terminated by the same planes as the dodecahedron, the only difference being that the side planes are not equal to the top and bottom planes, but we preserve the same angles and inclination of the planes to the vertical axes.

We do this in the following manner: We give the dodecahedron a hexagonal orientation, then the vertical axis is cut by three equally inclined planes. By hexagonal orientation is meant that orientation which is assumed by a portion of a regular dodecahedron Whenresting on a plane` that is defined by an equilateral triangle formedl by joining alternate vertices of the hexagonal trace of the edges of a regular dodecahedron. We then make an elongated hexagonal form to t the sides of our dodecahedron. We then place in this form our dodecahedron and make a wax* ends of our prisms at right angles to the vertical' axes so that they will t vertically on our plates. These metal forms are then mounted on our plates in the proper positions so that the sides of our prisms are parallel to each other and to the y median plane of the face or central vertical plane of the body, which is represented in our articulator by a line in the center of the plate. We can place these prisms any distance apart as long as they are orientated as above mentioned, but in the present instance we use an equilateral triangle to position them.

These prismsare placed at the angles of the triangle sothat the weight of the upper artificial teeth, models, etc., will fall within its angles so that the prisms will remain in contact during articular movements. In other words, We keep the center of gravity within the triangle during articular movements. When we do not depend upon the center of gravity holding the prisms in Contact during articular movements, We use springs at the proper positionsl to hold the prisms in contact in movements.

The opening or so called hinge movement is made by the plain line part of the articulator. The various other movements of the jaws are imi'- .tated by the movements of the ends of the prisms,

one plate with prisms attached being movable, the other plate with prisms attached being fixed or stationary.

The three main movements, the protrusive, the right lateral and the left lateral are made by moving the prisms in the directions of the terminating edges of the prisms that intersect the vertical axes and we make any other intermediate movements that we wish to by movements in any other directions than those mentioned that we think the jaw moves in. For instance we can imagine one of the prisms more or less stationary and move the other two in imitation of the so-called rotary movements'of the jaw.

It will be observed that in the protrusive movements of the articulator whenvmoved as directed, the plates with the prisms attached move directly forward in exactly the same manner as the natural jaw does.

It will also be observed that since the sides of these prisms are parallel to each other, any number of prisms could be usedy as guiding planes. Therefore in our articulator We do not limit the number of guiding planes or surfaces, but in this particular articulator we use three prisms on each plate as described.

It will also be observed that the terminated prisms could be of diierent heights as long as the guiding surfaceswere parallel or inclined to the vertical axes at the same inclinations; therefore we do not limit the heights of the prisms.

It will also be observed that the prisms could be placed any distance apart as long as they were yproperly orientated in respect to each other and to the center of gravity to prevent tipping during articular movements. Therefore, We do not limit the width of the articulator.

This application is a division of my previously filed application, Serial No. 695,711, led Oct. 28,

`1933, now Patent No. 2,027,003, dated April 14,

The following specication describes examples of the invention and the claims define the scope of the invention, reference being made to the accompanying drawings forming a part of the specification, by numerals in the specification which correspond to similar numerals on the drawings.

In the drawings- Figure l is a plan view of an articulator constructed in accordance with the invention.

Figure 2 is the rhombic dodecahedron and two of its faces showing one of the dihedral angles and the plane angles of one of its faces. Only the front side is shown in drawings.

Figure 3 shows the vertical and end views of the hexagonal form that ts around the rhombic dodecahedron, which is shown enclosed in 'the end View, that is used in making 5U in Fig. 8 and 5| in Fig. 9.

Figure 4 is a fragmentary diagrammatic View of the device shown in Fig. 5.

Figure 5 is a side elevation of an articulator 10 showing the adjusting means for moving the upper jaw denture model.

Fig. 6 is a horizontal section taken on the line 6-6 of Fig. 5.

Fig. 7 is a section showing the parts oi one of 15 the adjusting or guiding elements which move the upper jaw denture model.

Figs. 8 and 9 are perspective views, respectively, of the upper and lower parts of the guiding or adjusting element shown in Figs. 5 and 7.

Fig. 10 shows the rhombic dodecahedron Yand the hexagonal form that is used in making 50 and 5|, a part being broken away to better show the relationship before making the wax form.

Fig. 11 shows the vertical or end view of the rhombic dodecahedron and the hexagonal form surrounding it.

In accordance with the invention as illustrated in Figs. 1 to 9 inclusive, the articulator includes l y three plates, consisting of atop plate III, and inl`30 termediate plate Il, and a bottom or base plate I2. These plates are similar in size and shape, each being square in the present instance, but it is to be understood that these plates may be of any shape. The top plate and base-plate I2 are 53'5 rigidly connected to each other in horizontal superposed spaced parallel relation by three bolts I3 and nuts I4. The plates I0 and I2 are maintained in spaced parallel relation by tubular spacers I5 which surround the bolts I3. The g. plate I I is arranged between the plates ID and I2, and has openings I6 therein through which the bolts I3 and their spacers I5 extend respectively. The openings I6 are suciently large in order to allow the intermediate plate II to have the;V necessary lateral movement in an inclined plane. 45 The topplate Ill has arranged on its upper surface a lower jaw denture model holder II of any preferred type, and is ixedly secured as at I8. The holder I1 is positioned so that when the low- ,y er jaw denture model is applied thereto, it will be disposed substantially centrally of the plate I0. A vertically adjustable bracket is employed and consists of sections I9 and 20, each of which is of L shape. The bracket section I9 is securedgu to the plate II by suitable fastening elements 2|, the plate II having an opening 22 to receive the section I9 therethrough and also the section 20, the latter having an elongated slot 23 therein. Set screws 24 carried by the bracket section I9 and extending through the slot 23, engage the section 20 to hold the latter in various desired positions of adjustment. A bearing member 25 is secured to the upper end of the adjustable bracket section 20, as at 26. This member 25 hasA an upstanding lug 21 on one side, with a hole 28 therein for a purpose to appear. A plate 29 isl pivotally or hingedly connected, as at 30, with the bearing member 25. The plate 29 has a boss on theunder side thereof, and a tapped hole 3| extends 70 through this plate and said boss; Use is made of an upper jaw denture model holder 32, the same having one or more slots 33 therein to'accommodate a set screw 34 which may be screwed in the hole 3| to clamp the holder 32 in various of said'f positions of adjustment. From the foregoing it will be obvious that the model holder 32 may be adjusted in a plane perpendicular to the plate I I and also backward and forward with respect thereto. Full lower and upper denture models 35 and 3B are shown applied respectively to the holders I'I and 32, each of said models consisting of the usual plaster of Paris or other suitable material, and artificial teeth.

In using the articulator in conjunction with the guides 54, a pin 45 is inserted in the hole 28 in the lug 21, and this pin bears on the plate 29 to prevent the same from having swinging or pivotal movement, and maintains the holder 32 substantially parallel to the top plate I0. The guides 54 may then be used as guiding planes for the movements of the artificial teeth of the models 35 and 36, while being constructed.

Figure 4 is a diagrammatic View of the device shown in Figs. 1 and 5, in order to more clearly exemplify the manner in which the upper denture model 36 may be moved with respect to the lower denture model 35 in accordance with the invention.

In using the articulator, means shown in Figs. 5 to 9 inclusive are used. The said means consists of three pairs of elements, the elements of each pair being designated 50 and 5I. These pairs of elements 5I! and 5I are disposed between the plates I I and I2, at points so that aline drawn through these points will dene an equilateral triangle positioned accurately with respect to the center of gravity of the plate II.v Each of the elements 5I! is turnably connected with the plate II by a screw 52, and each of the elements 5| is xedly secured to the plate I2 by a screw 53. The opposing ends of the elements 50 and 5I of each pair have dihedral formations 54, which cooperate with each other by turning or moving the element 50. In other words, the elements 50 and 5I having the formation 54 constitute prisms having their faces disposed in a three-fold or trigonal symmetry about the opposing ends of the elements 5l! and 5I, or abouttheir vertica1axes,andin which the planes of said faces cooperate with each other to produce the desired movement. Therefore, it will be obvious that the plate II may be adjusted by manipulating the elements 50 to cause a movement of the upper model 3B corresponding to the movement of the plate II. In Fig. 10 is shown a dodecahedron inclosed in a hexagonal form of metal; this hexagonal metal form is held in a vertical position as shown in the illustration, and inlay casting wax is melted and poured into the hexagonal form, and when the wax is very nearly congealed the thumb is placed onthemelted wax at the end of the prism, thus creating pressure on the wax and enabling a good impression to be obtained of the three equally inclined planes of the dodecahedron; after obtaining the wax impression it is cast in metal, the dodecahedron is removed from the inside of the hexagonal form and the metal casting produced from the inlay wax impression of the end of the dodecahedron is placed in the hexagonal form in Fig. 10 and inlay casting wax is melted and poured into the hexagonal form, and onto the metal form contained therein, thus obtaining an impression of the end of the metal form casting; this inlay wax impression is then cast in metal.

We thus obtain hexagonal prisms terminated by the same planes as the dodecahedron in Fig. l; these prisms constitute the elements 50 and I and have the formation 54, and cooperate with each other to produce the desired movements in the articulator as has been described.

In Fig. 11 is shown a crosssection of the dodecahedron and the hexagonal metal form shown in Fig. 10, showing the dihedral angles of the dodecahedron to be 120 degrees; italso shows the obtuse and acute angles of each face of the dodecahedron, and we obtain an impression of these inclined planes as described in the description of Fig. 10. The movement of the artificial teeth always will be parallel to the planes of the adjusting means described. In this manner the desired occlusion and articulation of the artificial teeth may be obtained. f

What I claim is: Y

1. A dental articulator comprising an adjustable jaw denture model holder, a stationary jaw denture model holder with respect to which said iirst holder may be adjusted, and means to adjust said first holder, said means consisting of prisms having cooperative guiding faces disposed in trigonal or three-fold symmetry about their vertical axes.

2. A dental articulator comprising an adjustable jaw denture model holder, a stationary jaw denture model holder with respect to which said first holder may be adjusted and means to adjust said rst holder, said means consisting of fixedelements and vopposing rotatable elements arranged in cooperative relation to said xed elements respectively, the opposing surfaces of said elements being angular depressions and elevations.

HOWELL BOATN ER. 

